Field of the Invention
The present invention relates to a fingerprint identification apparatus, especially to a fingerprint identification apparatus having low cost and high packaging yield.
Description of Prior Art
Biometric recognition technologies have rapid development due to the strong request from electronic security applications and automatic access control system. The biometric recognition technologies can be classified into fingerprint recognition, iris recognition and DNA recognition and so on. For the considerations of efficiency, safety and non-invasiveness, the fingerprint recognition becomes main stream technology. The fingerprint recognition device can scan fingerprint image by optical scanning, thermal imaging or capacitive imaging. For cost, power-saving, reliability and security concerns, the capacitive fingerprint sensor becomes popular for biometric recognition technology applied to portable electronic devices.
The conventional capacitive fingerprint sensors can be classified into swipe type and area type (pressing type), and the area type has better identification correctness, efficiency and convenience. However, the area type capacitive fingerprint sensor generally integrates the sensing electrodes and the sensing circuit into one integrated circuit (IC) because the sensed signals are minute and the background noise is huge in comparison with the minute sensed signals. In conventional area type technique, holes are defined on the protection glass of the display to arrange the fingerprint identification IC chip therein and sapphire film is used to cover and protect the fingerprint identification IC chip. Through-silicon via (TSV) technique is used to lead the conductive wires to backside of the fingerprint identification IC chip. As a result, the material cost and package cost is high while the yield is influenced. There are development trends to simply the package the fingerprint identification IC chip and to enhance the sensing ability. The fingerprint identification IC chip is desirably packaged under the protection glass to reduce cost and enhance product lifetime/durability.